Tomography based pore-level optimization of radiative transfer in porous media

A non-energy-partitioning Monte Carlo Ray Tracing (MCRT) model is employed to optimize radiative transfer in porous media. The pore level geometry is incrementally modified using 3D equivalents of image manipulation algorithms such as erosion, dilation, opening, and closing. Subsequently, direct, pore-level analysis of radiative transfer is carried out for each modification step to optimize the pore-level geometry for maximum absorptance. Results have been obtained for an opaque, diffusely or specularly reflecting solid phase within a non-participating void phase. Model media studied are: (i) reticulate porous ceramics (RPCs) and (ii) packed beds of CaCO₃ particles. The extinction coefficient and the forward scattering fraction have been determined for the media via a two-flux model of radiative transfer. Optimum porosities for maximizing absorptance at given medium thicknesses are then obtained from the analytical model. For the RPC, the forward scattering fraction varies between 0.38 and 0.57, and the extinction correlation coefficient varies between 9.56 and 7.03. For the packed CaCO₃ particle bed, the forward scattering fraction varies between 0.6 and 0.72, and the extinction coefficient varies between and 2.84 and 2.14.